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        var str1 ="hello world";
        var str1 ='hello world';
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        console.log(str2)
        //单引号里只能放双引号，双引号里只能放单引号，不能重复使用两个一样的引号
        var str4 ='小明说：“小红很漂亮”'
        console.log(str4);
        var str ="java";
        //js中先运算等号右边的语句
        str  = str +"script";//字符串中+号是连接的意思 JavaScript
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